In recent years, it has become common practice to ship goods in metal containers that are adapted to be transported by ship and tractor trailers. As a result of the ships carrying a substantial number of the containers, it is necessary to maintain an inventory of trailers at the unloading and loading sites. Such takes up a substantial amount of space. Normally, the ports where the containers are shipped are limited in size presenting a problem for storing large numbers of trailers waiting to be used. It has been common practice in the past to transport the trailers in a stacked configuration. However, when they are placed one on top of the other, they are normally inverted requiring each trailer as they are being unstacked to be turned over so as to properly position the wheels on the ground for use. This oftentimes causes damage to the hydraulic equipment associated with the trailers.
In U.S. Pat. No. 4,611,962 there is disclosed a container chassis bundling system wherein trailers are stacked upon each other. Each of these trailers require substantial modifications so that the trailers can be securely stacked one upon the other.